70 terms

Coasts [IGCSE Geo]

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Coastal landform
Feature on the Earth's surface that is part of the terrain found at the coast eg. a headland or beach.
Fetch
Length of water over which a given wind has blown - the bigger the fetch the bigger the waves.
Constructive wave
Low and less powerful waves created in calm weather which break on the shore and deposit material, building up beaches. Swash is stronger than the backwash.
Destructive wave
Big, strong waves created in storm conditions when the wind is powerful and has been blowing for a long time. Erode the coast. Backwash stronger than swash.
Geology
The study of rocks.
Swash
Water washed up the beach when a wave breaks.
Backwash
Water from a wave runs back down the beach.
Coastal Erosion
Wearing away and breaking up of rock along the coast.
Bar
Ridge of sediment which forms across the mouth of a river at the coast.
Long shore drift
Transport of sand and pebbles along the coast.
Abrasion (Corrasion)
Caused by waves picking up materials such as pebbles or shingle, and hurling them against a cliff face, wearing the surface away
Solution (Corrosion)
Coastal rocks are dissolved and removed by sea water
Hydraulic action
Air may become trapped in joints and cracks on a cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion.
Attrition
Material carried in sea water becomes smaller and rounder as it bumps into each other (creating sand).
Cliff retreat
Cliffs move backwards due to erosion.
Wave cut platform
Narrow flat area of rock found at the base of a sea cliff. It is covered by water at high tide but exposed at low tide. Formed through erosion (by waves) of a former cliff face
Coastal arch
Hole through a headland.
Sea stack
Vertical column of rock near a coast.
Stump
Short sea stack.
Bay
Indentation of the shoreline. An indented area of land normally found between two headlands. Bays are usually more sheltered so there is less erosive power, and more deposition. This means you often find beaches in bays.
Headland
Section of land jutting out into the sea. Waves refract around headlands so they experience a lot of erosion forming features like arches and stacks
Groynes
Wooden, stone or concrete barrier built at right angles to the beach.
Beach nourishment
Dumping or pumping sand from elsewhere onto an eroding shoreline to create a new beach or to widen the existing beach.
Coast
The interface (meeting point) between land and sea.
Salt marsh
Coastal ecosystem in the upper coastal intertidal zone between land and sea.
Sediment
Particles of rocks and minerals & the remains of plants and animals that are moved and deposited in a new location. Can be as small as a grain of sand or as large as a boulder.
Polyp
Coral organisms
Atoll
Ring-shaped coral reef with a lagoon in the centre.
Bleaching
Process whereby coral colonies lose their colour, due to the loss of the microscopic algae living in their tissues.
Fringing reef
Coral reefs which grow near the coastline separated from the shore by narrow, shallow lagoons.
Barrier reef
Reef of coral running roughly parallel to the shore and separated from it by a wide, deep lagoon.
Coastal management strategy
Physical management of the coast attempts to control natural processes such as erosion and longshore drift.
Ecosystem
Living community of plant and animals sharing an environment with non-living elements such as climate and soil.
Conservation
Protection of wildlife and of natural resources such as forests, soil, and water.
Mangrove
Tidal habitat comprising trees and shrubs that are adapted to living in salty conditions.
Pollution
Introduction of harmful materials into the environment by humans at a rate faster than the environment can deal with them.
Biodiversity
All the different kinds of living organisms within a given area.
Salinity
Saltiness or dissolved salt content of a body of water.
Beach profile
Cross-section of a beach.
Cliff
Vertical expanse of rock, common at coasts, where coastal erosion, weathering and mass movements are active. The nature of the cliff depends on the nature of the rocks (e.g. their hardness)
Wave cut notch
An indent at the base of the cliff formed by undercutting.
Spit
Extended stretch of beach material that projects out to sea and is joined to the mainland at one end.
Beach
Accumulation of material (sand, shingle and pebbles) between low and high water marks. A typical beach will have three zones: backshore, foreshore and offshore.
Coastal sand dune
A hill of sand built by wind at the coast.
Land use
How land is used by people.
Rip rap
Large boulders piled up on the beach to protect shorelines.
Afforestation
Planting of trees.
Reclamation
Process by which new land is created.
Offshore headland
Artificial headlands built parallel to the coast.
Tide
Cyclic rise and fall of seawater caused by the gravitational pull of the moon and the Sun.
Prevailing wind
Direction from which that the wind most frequently comes.
Wind strength
How strong the wind is.
Sea wall
Wall built on the edge of the coastline.
Soft engineering
When people work with natural processes eg. beach nourishment.
Hard engineering
When people try to stop natural processes eg. sea wall.
Coastal deposition
When the sea loses energy, it drops the sand, rock particles and pebbles it has been carrying.
Saltation (at the coast)
Sand grains are bounced up the beach by wind.
Tombolo
Spit joining an island to the mainland.
Dredging
Gathering up bottom sediments carried out underwater, in shallow areas.
Delta
Depositional landform that forms from sediment carried by a river as the flow leaves its mouth and enters the sea.
Lagoon
Shallow body of water separated from a larger body of water by barrier islands or reefs. Found in atolls and behind coastal bars.
Process
Something which changes the geography of an area eg. erosion, reclamation, long shore drift.
Embankment
Mound of material built up to protect the coast from flooding.
Wave length
The distance between two successive troughs or crests
Crest
The top of a wave
Trough
The low area between two waves
Wave frequency
The number of waves per minute
Wave refraction
This refers to how a wave bends as it approaches the coastline. This is due to the variation in the depth of water underneath - as in, some parts of the wave are touching the sea floor, which slows down the wave, while other parts of the wave are in deeper water and moving faster. When the depth under a wave crest varies, this causes the wave to bend (refract).
Concordant coastline
Where rock outcrops run parallel to the sea, often producing straighter coastlines
Discordant coastline
Where rock outcrops are at right angles to the sea, often producing headlands and bays. Soft, weaker rocks are easily eroded resulting in bays. More resistant rocks erode at a much slower rate, therefore protrude as headlands